Fuel pump



March 29, 1960 G. E. KEssNr-:R 2,930,323

' FUEL PUMP Filed Feb; 8, 1957 was IN V EN TOR.

United States Patent() i FUEL PUMl George Edward Kessner, Rock Springs, Wyo.

Application February 8, 1957, Serial No. 639,064

1 Claim. (Cl. 10S-'44) This invention relates to the distribution of uid including by the use of force, such as by pumps or other mechanical means, and more particularly to fuel pumps capable of producing relatively high pressure for the pumping of fuel or other liuid.

The invention relates specifically to hydraulically actuated pumps designed primarily to pump high pressure gasoline or other fuels which do not have lubricating qualities at a pressure approximately of 2,500 pounds per square inch.

Pumps heretofore in use have been subject to damage by water or other lluids or'substances, such for example as those often found in fuel. Further, such pumps have not been able to handle satisfactorily certain uids, such as gasoline or other fuels which do not have lubricating qualities. Also, it has been necessary that the parts of pumps be exact or precise in measurement resulting in substantial expense and prior pumps have been subject to criticism because of these and other objectionable features.

It is an object of the invention to overcome the criticisms enumerated and to provide a relatively simple and inexpensive hydraulic actuated high pressure fuel pump of relatively inexpensive construct-ion and few parts, which is of new and unique basic design, which will not be damaged by water or other impurities often found in fuel, as well as a high pressure fuel pump in which the tolerances do not have to be precise and the principle of which pump may be applied in various ways to obtain.

pressure on the order of 2,500 pounds per square inch.-

Another object of the invention is to provide a pump which can be easily produced and applied to be driven from a rotatable cam shaft.

Other objects and advantages of the invention will b apparent from the following description taken in conjunction with the accompanying drawing wherein the figure is a longitudinal vertical section illustrating one application of the invention.

Brietiy stated, the invention is a high pressure fuel pump being adapted to be driven in any desired manner as, for example, by a cam on a shaft. The invention includes a pump body having a cylinder with an inlet and an outlet each controlled by a check valve. A piston is disposed in said cylinder and in spaced relation to the first piston is a second with a mass of liquid between them so that the lirst piston can be driven from the second by such intermediate mass of liquid, the operation of one of the pistons from the other being in accordance with whether or not said mass of liquid between said pistons is relieved, and the driving action being cushioned by such body of liquid. Means are provided for opening and closing a relieving passage.

With continued reference to the drawing, the pump of the present invention comprises a body having a central longitudinal bore defining 'a cylinder 11 with which inlet and discharge passages 12 and 13, respectively, provide for the admission and discharge of iiuid employed in the pump. The inlet and discharge passages 12 and 2,930,323 ce Patented f Mar. 29, 1960 13 are of a size adequate to permit the necessaryuid to hereinafter described is provided for assuring ow of fluid in only one direction into the cylinder through the inlet and from the cylinder through the outlet.

The inlet passage 12 communicates with an enlarged bore 14 which receives a spring 15 which bears against a ball valve 16 located in a position to close the end of a passage 17 in an externally threaded inlet coupling 18 which engages an internally threaded opening 19 in the body 10. The coupling 18 preferably has a tapered inner end 20 adapted to engage a gasket 21 to prevent leakage through the threads between the coupling and the body. The inner end portion ofthe coupling 18 and the corresponding portion of the opening 19 preferably are unthreaded.

Within the bore which forms the cylinder 11, at the end of the cylinder, is a wall 22 in which the discharge passage 13 is located. This discharge passage provides communication with the cylinder and an enlarged internally threaded coupling 24 having a bore 25. The inner end of the coupling is similar to the inner end Yof the inlet coupling 18 and is adapted to bear upon a gasket 2.6. Also the inner end of the bore 25 is provided with a chamber 27 in which is located a helical spring 28 which engages a ball valve 29 which seats in the discharge opening 13. Fluid passing into and from the cylinder must pass the ball valves 16 and 29.

Actuating means is provided for causing the flow of iiuid into and from the pump which comprises a piston 30 in the upper portion of the cylinder 11 and normally urged away from the wall 22 in which the discharge passage is located by means of a helical spring 31 having one end bearing against the wall 22 and its opposite end extending around a reduced concentric guide portionv 32 of the piston 30. Retraction of the piston 30 is limited by means of la pin 33 located in a transverse opening 34 in the valve body, such pin having an enlarged externally threaded head 35 which engages the enlarged internally threaded portion of the body 10. The piston30 is relatively short and is adapted to be moved by iluid against its rear face under pressure supplied by the piston to force discharge of fuel from the cylinderby theV ball valve 29. Such hydraulic fluid is adapted to be subjected to the pressure of a substantially longer piston 37 located in the cylinder 11 and having a grooved inner end portion 38 for controlling the admission of hydraulic liuid through a port 39 having communication with an internally thread-V ed opening 40 adapted to have a connection with a uid line, not shown. When the piston 37 moves upwardly past the orifice 39 it traps iluid between it and the piston 30, thus serving to drive piston 30 through the hydraulic fluid. Fluid in the end of the cylinder 31 will cause the valve 16 to remain against its seat `and the valve 29 to leave its seat to permit the discharge of uid through the pump 25 and the coupling 24. Reverse movement of the piston 37 will uncover the port 39, thereby permitting relief of pressure on the fluid between the two pistons to thus accommodate for any leakage in the system. The

piston 37 may be reciprocated and rotated by any desired means, as vfor example, such piston may have a gear 41 engaged by a rack or gear segment 42 controlled from any desired source so that rotation of the piston can be accomplished.

The end of the piston 37 is provided witha reduced neck 43 and an enlarged rounded head 44 whichrhead iits within a hollow member. 45 which forms in effect a socket having inturned portions which engage beneath the head 44. The socket 45 has an externally threaded stud portion 46 on which is adjustably mounted on internally threaded extension 47 held in place by means of a locknut 48. The extension `47 has an enlarged ange 49 and a helical spring 50 is locatedaround such extension and engaged said flange with its remote end engaging a perforated plate 51 held in place by a snap ring 52. The extension member 47 and helical spring SQ are disposed vL/ ithin an open ended cylinder or tappet 53 in contact with a cam. 4 on a driven shaft not shown. When the shaft is,dr ive`n and the cam rotatesit moves the tappet in the piston 37 which` causes iluid to. be taken intoY and discharged from the pump.

It will be obvious to those skilled in the art that varionschanges maybe made in the invention without departingA from the spirit and scope thereof and therefore the inventionis n ot limited by that which is illustrated in the drawing anddescribedin the specification, but only as indiatedvin the accompanying claim.

What is claimed is:

Afhigh pressure fuel pump for liquids comprising a body having a cylindrical bore of uniform diameter formed therein, a iirst piston mounted in said bore for movement, said first piston havingV a concentric projection at. one end of less diameter than the diameteiof piston, a compression spring engaging said one end of said piston andl surrounding said projection, shoulder means on said body engaging said compression spring whereby said compression spring urges said rst piston in aj direction away from said shoulder means, and inlet and 'ancutlet to the space communicating with said one end 4 of said piston for the reception and discharge of liquids, check valves controlling the flow through said inlet and outlet, said body being provided with a transverse opening adjacent the end of said first piston away from said projection, a pin mounted in said opening to limit the movement of said first piston in a direction away from said shoulder means, a second piston slidably mounted in said bore, an entrance opening in said body providing a passage for hydraulic fluid into the portion of said bore in which said second piston reciprocates, means on said second piston to, control the opening for said hydraulic uid whereby a fluid link of predetermined size is provided between said irst and second pistons, and means to positively reciprocate said` second piston and resilient means independent of said first piston for urging said second piston in a direction away from said shoulder means and against said means for positively reciprocating saidseond piston.

References Cited'in the file of this patent UNITED STATES PATENTS 2,041,468V Grubbs May 19, 1936 2,192,387 Schlaupitz Mar. 5, 1940 2,397,136 French Mar. 26, 1946 2,535,535 Fleck Dec. 26, 1950 2,624,284 Straub Ian. 6, 1953 

